Electrical heater.



F. KUHN. ELECTRICAL HEATER.v APPLIoA'rIox FILED AUG. 1o. 1909.

979,515. Patented 1101211910.

UNITED STATES PATENT OFFICE.

FRANK KUHN, OF DETROIT, MICHIGAN, ASSIGNOR TO AMERICAN ELECTRICAL HEATERCOMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

ELECTRICAL HEATER.

Specification of Letters Patent.

Patented Dec. 27, 1910.

To all 'whom it may concern:

Be it known that I, FRANK KUHN, a citizen of the United States ofAmerica, residing at Detroit, in the county of Wayne and State ofMichigan, have invented certain new and useful Improvements inElectrical Heaters, of which the following is a specification, referencebeing had therein to the accompanying drawings.

It is the object of the invention to obtain a construction of electricheater in which the heating unit is adapted to localize the heatingeffect so as to restrict the same to a comparatively small area.

It is a further object to render the unit readily attachable anddetachable and to provide a good heating contact.

With these objects in view, the invention consists in the constructionas hereinafter set forth.

In the drawings-Figure l is a vertical central section through theheater as applied to a coffee percolator; Fig. 2 is a perspective viewof the unit detached; and Fig. 3 is a horizontal section.

My invention is more particularly designed for use in connection withcoffee percolators, and such a construction is illustrated in thedrawings, but it is obvious that it is also applicable to other uses.

As shown, A is the bottom of the coffee pot, B is a centrally-arrangedriser tube, through which the heated water is passed to thecoffee-holding receptacle, these parts being of any suitableconstruction, and not forming any portion of the present invention.

It is usual in the construction of percola- -tors of the typeillustrated to provide a small pocket below and in alinement with thetube B, said pocket having its walls formed integral with the bottomportion of the pot and being heated through the me-l dium of saidbottom, to which the gas flame, or other heater, is directly applied. Inthe present construction I have formed this pocket, C, in a member Ddepending from the bottom A of the receptacle. The member D issurrounded by a heating unit E, which is clamped thereon, and from whichthe heat is conducted directly into the iuid within the pocket withoutfirst passing into the bottom A of the receptacle. Thus, the greaterportion of the heat generated `oes at once into the water within the pocet,

and in this respect my construction has an advantage over the usualconstructions where a' considerable area of the bottom of the receptacleis heated simultaneously withl the heating of the pocket.

More in detail, the member D is preferably formed with a shoulder Fabutting against the bottom A and a threaded portion G above the bottomwith which a lock nut H is engaged to clamp the parts together. Thedepending portion Dl of the member D is preferably tapered and iscircular in section, while at the lower end of this portion is athreaded socket D2 for engaging a winged clamping screw I. The head ofthis screw bears against the lower end of the unit E and forces the sameupward upon the tapering pin to insure a close metallic contact.

The unit E preferably consists of a metallic spool J longitudinallyslotted upon one side, as at J and surrounded by convolutions of aninsulated helix K. This helix K is formed of suit-able resistancematerial and is preferably in the form of a flattened wire or ribbonwound between outer and inner insulating sheaths K', preferably of mica.At the opposite ends of the spool J are retaining flanges J 2, but theseare slotted at J 3 to permit of free contraction or expansion of thespool. L is an outer case surrounding the spool J and M are insulatedterminal posts clamped upon a flattened -portion L of the outer case,being insulated therefrom, and connected respectively to the terminalends of the helix K.

With the construction as described, in use the unit E is engaged withthe tapering member D, to which it is clamped by the screw I. Inclamping, the slotted spool J is slightly expanded by being forced upthe taper of the member D, and as said spool is made of resilientmaterial it will be forced into firm contact with a portion of themember D. Thus the heat generated in the helix and conducted therefromto the spool will pass from the latter into the member D and into thefluid within the pocket. On the other hand, the spool D and helix K areseparated by an air space from the outer case L so as to prevent theloss of heat in an outward direction and by nickel-plating the outercase, or otherwise producing a bright polished surface, the heat loss isreduced to the minimum.

In operation, the heat generated in the helix is sufficient to almostinstantaneously boil the water in the pocket C, from which it passesupward through the tube B, being displaced by cold Water from the outerreceptacle A.

What I claim as my invention is:

l. In an electrical heater the combination with a heating unit and amember to be heated thereby, one of said members being` provided -with atapering pin and the other with a socket detachably engaging said pin,said pin and socket being in heat conducting contact and clamping meansfor holding said members in engagement.

2. In an electrical heater the combination of a member to be heated anda heating unit, one of said members having a tapering pin and the otherbeing provided with a longitudinally slotted tapering socket engagingsaid pin, and interclamping means for forcing said tapering pin intosaid socket. l

` 3. In an electrical heater the combination of a member to be heatedand a heating unit, one ofv said members being provided with a l'pin andthe other of said members being provided with a socket detachablyengaging said pin, said socket member being resilient and expanded byengagement of said pin.

4. In an electrical heater, a member to be heated provided with aprojection of smaller cross-sectionall area than said member, a heatingunit comprising a sleeve or spool adapted to engage the projection, aresist- 'ance conductor wound upon said spool and insulated therefrom, acasing surrounding 'the s ool, and vinsulated contact members secure tosaid'casing and connected with the vend'sof said resistance conductor.

5. In an electrical heater, a heating unit,

comprising'a split ':s'leeve, a resistance con- 7. The combination Witha receptacle, ofva hollow member of lesser cross-sectional area than thereceptacle depending from the same, andforming a fluid-containingpocket, and

an electrical heating unit in the form offa .i detachable sleevesurrounding said dependf 1.1

ing member.

8. The combination With'a receptaclmof it' '65 a hollow member of lessercross-sectional 'area than the receptacle depending from 'the same,

and of tapering form; a' tapering sleeve for engaging said taperinghollow-member, `and -f an electrical heating resistance said sleeve andinsulated therefrom.

9. In an electrical heater the combination with a heating unit, of vamember: to *be "i:

heated thereby, one of saidirnember provided with a tapering pin and: thwith a socket detachably engagin,g""th pin', the contacting faces ofthe'pin and socket bein of heat conducting metal, and means .l

for orcing said tapering pin into the Socket. In testimony whereof Iailix my signature in presence of two Witnesses.

' FRANK KUHN. Witnesses:

NELLIE KINSELLA, JAMES P. BARRY.

